Any advise for my college project?

Hey every one, I'm working on a mock business for my intro to business class. Our business is an online college book rental and I could really use some advice on a couple issues.

1) The ever elusive problem here at SaleHoo, suppliers. I found ecampus here and I'm sure I can call the companies that make the books, any others would be helpful.

2) College text books are constantly being rewritten. Any ideas on what kind of 'shelf life' they would have. (how many years would they still be worth renting?) i think this would be my most important question, as this should prove to be the biggest factor in sales price and profit.

3) Ever ship textbooks within the U.S.? what do think the average price would be?

Several years ago I was going to get into this business. Right now, this is a big issue with college students and parents that pay thousand of dollars every year for books. Teachers kind of in hoots with the textbook makers get money from these companies for using a new textbook every year even though the books have no new info but simply a rearrangement of data.

I think its Amazon that is going to offer rentals to students to help offset the costs.

I think college textbook rentals is a great idea. I have a college student & believe me books are EXPENSIVE! 99% of the books he'll never ever use again. Here's a link for books you might want to check out.